A component having a semiconductor body in the at least one semiconductor junction between a first semiconductor zone of a first conduction type, the first semiconductor zone being arranged in an inner region in the region of a first side of the semiconductor body, and a second semiconductor zone, which adjoins the first semiconductor zone in the vertical direction, is described, for example, in DE 100 19 813 C2. In the case of this component, a third semiconductor zone that is doped more heavily than the second semiconductor zone is formed in the second semiconductor zone such that it adjoins the first semiconductor zone. When a voltage that reverse-biases the pn junction is applied, the third semiconductor zone is intended to rapidly reduce the electric field strength in the region of the pn junction and, overall, contributes to reducing the voltage endurance of the component in the inner region in order to shift the location of a possible voltage breakdown from the edge region—which has a lower voltage endurance than the inner region—into the inner region.
EP 405 200 A1 describes a semiconductor component that is in the form of an IGBT and has a pn junction that is formed between a p-doped collector zone and an n-doped base zone. Arranged in the base zone of this component is a heavily n-doped recombination zone, which is itself so highly doped that it prevents a punch-through of the space charge zone and which has cutouts in which a punch-through of the space charge zone is possible.
Problems in semiconductor power components may result from an excessively rapid (hard) transition from the conducting state to the blocking state, as is explained briefly below.
In power components, the second semiconductor zone is doped more weakly than the first semiconductor zone and is essentially used to receive an applied reverse voltage when the semiconductor junction between the first and second semiconductor zones is blocked.
In the case of a forward-biased semiconductor junction, this second semiconductor zone is flooded with charge carriers. If this initially forward-biased semiconductor junction is subsequently reverse-biased, a current initially continues to flow, on account of the charge carriers present in the second semiconductor zone, until these charge carriers have been dissipated from the second semiconductor zone.
The change in current over time (di/dt) when turning off the component leads to induced voltages across parasitic inductances (for example in leads) which are inevitably present and increase as di/dt rises. In order to limit these voltages, it is desirable, when turning off the component, to avoid “current chopping” with an extremely large change in current over time and the associated high voltages across parasitic inductances.